Gearbox

ABSTRACT

A multi-gear, manual transmission, especially for utility vehicles, with at least partially automatized gear shifting or with a manual gear shift, in which the gear synchronization is carried out by motor guidance and wherein the transmission possesses a forward shift-group, a main-shift-group and a post shift-group, whereby the pre-shift-group is designed as a planetary gear set ( 2 P) and a support member of the planetary gear set is constructed as a friction brake, which is active in the slow gear-shift position and thereby assumes the function of a start-up clutch.

The present invention concerns a multi-gear, manual transmission,especially for utility vehicles, with at least partially automatizedgear shifting or with manual gear shifting, in which the gearsynchronization is carried out by motor guidance and which transmissionpossesses a forward shift-group, a main shift-group and a postshift-group.

A multi-gear transmission, comprising a main-transmission, an area-grouptransmission and a reversing gear train, has been made known by DE A 3619 329 of the applicant. These transmissions transfer power from oneinput drive shaft to an output drive shaft through a plurality ofgearshifts by means of gears, synchronous-shift clutches and shiftablefriction clutches, whereby two power branches are provided and thepower, in every case, is only transferred by one power-branch. In eachpower-branch, one friction clutch and at least one synchronous-shiftingclutch act sequentially, one after the other, in the direction of powerflow. The two friction clutches are placed on the input drive. Thereby,a first driving speed area is created with shifting steps of largeincrements, and a second driving speed is created with shifting steps ofsmall increments, whereby in a limited total travel speed area, thedrive motor can be employed at a higher speed of rotation and greaterpower, without having to eliminate a large total speed area.

In the case of this known transmission, as well as in all other shifttransmissions in use today, driving clutches and the correspondingtransmissions are two separate component groups. The driving clutch, inthis arrangement, along with the flywheel and the transmission, isconnected to the motor block. A rigid, that is a screwed connection,between the clutch and the transmission does not exist. If clutch andtransmission, as has been often desired by manufacturers of vehicles,are to be furnished to make a system unit on a production line, thentoday, two loose parts, always separated one from the other aredelivered. In this way, a careful tuning is needed between these twoseparate components since not only the torque, but also the inertia ofthe clutch plate, as well as the principal dimensions and the like mustbe precisely matched to one another.

To bring into actuality the cost lowering potentialities inherent in thereduction of complexities for the vehicle manufacturer by providing acombined system with a smaller mounting expense, it is obviouslydesirable, to connect these two individual parts to one another, thatis, to integrate the clutch into the transmission.

On this account, the purpose of the present invention is to create amulti-gear shifting transmission, especially for utility vehicles, inwhich the driving clutch is integrated into the transmission.

Starting from a multi-gear shifting transmission of the kind describedin the introductory passages, the achieving of the purpose of theinvention will be accomplished with the features stated in thecharacterizing part of claim 1. Advantageous embodiments are describedin the subordinate claims.

In accord with the invention, the proposal has also been made, that inthe case of a multi-gear shifting transmission with at least a partiallyautomatized transmission shift or with a manual-shift transmission, inwhich the gear synchronization is carried out under the guidance of themotor, and in which the manual shift transmission possesses at least twogear train groups, the forward shift-group is comprised of a planetarygear set and the support member of the planetary drive is designed as afriction brake, which acts in the slow shift position and on thisaccount takes over the function of a start-up clutch.

Besides the already mentioned lowering of manufacturing costs andreduction of the complexity, this being done by the delivery of anintegral system with a lowered time and expense for assembly, theadvantage is achieved with the invented combined transmission, that agreater reliability of the shift-gear train is made possible, along witha better co-action of the two parts with one another, namely the clutchand the transmission.

At the same time, again an advantage is gained, in that, contrary to aconventional gear train, first, the clutch with its pressure plate,second the clutch plate with the torsion damper, third the releasebearing and its cylinder can all be dispensed with. Besides thementioned lowering of costs, this leads to a substantial decrease in theweight. The conventional forward shift-group in the form of a 2-shiftreduction gear train, is replaced with a planetary gear set withconstant mesh transmission.

The invented clutch integration is described in connection with asixteen-shift transmission, designated as 2P×4V×2P, wherein V stands forthe leading gearing and P for the planetary gear set. Conventionalsixteen-shift transmissions normally exhibit the assembly 2P×4V×2P.

By means of the invented formulation of the forward (splitter)shift-group 2 being served by the planetary group 2P, as can be inferredfrom FIG. 1, the possibility is created, to brake and secure the supportmember—that member being the sun gear 4 of the input side planetary gearset—with a friction clutch 6. This support member of the planetary gearset is designed thus in the slow or low shift position and takes on thefunction of the starting clutch. A friction brake is substantially morefavorable in cost than is a conventional start-up clutch.

A further provision is made to allow the friction brake or clutch 6,which serves as the starting clutch, to be made engageable by compressedair being supplied from a pressure supply 8 via a pressure line 10 tothe friction brake or clutch 6, wherein the brake is disengaged withoutpressure, and upon pressurizing, the friction brake or clutch 6 engages.Air pressure is already provided on board in every conventional utilityvehicle for other purposes and thus entails no additional costs.

Provision is further made, that the input planetary gear set 2P can beby-passed by a shape-fitted or lockup clutch 12, so that thereby, it ispossible to shift into a new or subsequent gear position.

The friction brake or clutch 6, which has assumed the function of thestart-up clutch, can either be installed in a dry-sump of thetransmission or, on the other hand, in the oil-lubricated wet-sump ofthe transmission (both only diagrammatically illustrated in FIG. 1).

It is emphasized, that in the entire remaining gear train, no furtherfriction-closure separating member is part of the assembly.

The multi-gear manual transmission 14 possesses the forward (splitter)shift-group (2P) 2, the main shift-group (4V) 16 and a post shift-group(2P) 18.

What is claimed is:
 1. A multi-gear manual transmission for a utilityvehicle in which the gear synchronization is carried out by motorguidance and the multi-gear manual transmission possesses a forwardshift-group, a main shift-group and a post shift-group, wherein theforward shift-group is a planetary gear set (2P) having a support memberconstructed as a friction brake, the friction brake functioning as astart-up clutch for the multi-gear manual transmission, also provided tothe planetary gear set (2P) is a shape fit clutch which also by-passessaid planetary gear set (2P).
 2. The multi-gear manual transmissionaccording to claim 1, wherein the friction brake is connected, via apressures fluid line, to supply of fluid pressure whereby, uponpressurization of the friction brake, the friction brake is engaged sothat the friction brake transmits driving torque to the main shift-groupand, when the friction brake is unpressurized, the friction brake isdisengaged and interrupts transmission of driving torque to the mainshift-group.
 3. The multi-gear manual transmission according to claim 2,wherein the supply of fluid pressure comprises compressed air which issupplied to the friction brake.
 4. The multi-gear manual transmissionaccording to claim 1, wherein the friction brake is in a dry sump brake.5. The multi-gear manual transmission according to claim 1, wherein thefriction brake is in a wet sump brake.
 6. The multi-gear manualtransmission according to claim 1, wherein the post shift-group is aplanetary gear set (2P).
 7. A multi-gear manual transmission for autility vehicle in which the gear synchronization is carried out bymotor guidance and the multi-gear manual transmission possesses aforward shift-group, a main shift-group and a post shift-group, whereinthe forward shift-group is a planetary gear set (2P) having a supportmember constructed as a friction brake, the friction brake functioningas a start-up clutch for the multi-gear manual transmission, and thefriction brake of the forward shift-group planetary gear set (2P) is theonly frictional engageable separating member of the manual transmission.8. The multi-gear manual transmission according to claim 7, wherein thefriction brake is connected, via a pressure fluid line, to supply offluid pressure whereby, upon pressurization of the friction brake, thefriction brake is engaged so that the friction brake transmits drivingtorque to the main shift-group and, when the friction brake isunpressurized, the friction brake is disengaged and interruptstransmission of driving torque to the main shift-group.
 9. Themulti-gear manual transmission according to claim 8, wherein the supplyof fluid pressure comprises compressed air which is supplied to thefriction brake.
 10. The multi-gear manual transmission according toclaim 7, wherein the friction brake is in a dry sump brake.
 11. Themulti-gear manual transmission according to claim 7, wherein thefriction brake is in a wet sump brake.
 12. The multi-gear manualtransmission according to claim 7, wherein the post shift-group is aplanetary gear set (2P).
 13. A multi-gear manual transmission for autility vehicle in which gear synchronization is carried out by motorguidance, the multi-gear manual transmission having: a splitter group; amain shift-group; and a range group; wherein the splitter group is aplanetary gear set (2P) having one component thereof constructed as afriction brake, and the friction brake, in a low gear-shift position,functions as a start-up clutch for the multi-gear manual transmission totransmit driving torque from the splitter group planetary gear set (2P′)to the main shift-group; and the friction brake of the splitter group isthe only frictional engageable separating member of the multi-gearmanual transmission.
 14. The multi-gear manual transmission according toclaim 13, wherein the friction brake is connected, via a pressure fluidline to supply fluid pressure whereby, upon pressurization of thefriction brake, the friction brake is engaged so that the friction braketransmits driving torque to the main shift-group and, when the frictionbrake is unpressurized, the friction brake is disengaged and interruptstransmission of driving torque to the main shift-group.
 15. Themulti-gear manual transmission according to claim 13, wherein the supplyof fluid pressure comprises compressed air which is supplied to thefriction brake.
 16. The multi-gear manual transmission according toclaim 13, wherein the fiction brake is in a dry sump brake.
 17. Themulti-gear manual transmission according to claim 13, wherein thefriction brake is in a wet sump brake.
 18. The multi-gear manualtransmission according to claim 13, wherein the splitter group has alockup clutch which, when engaged, passes the driving torque to the mainshift-group.
 19. The multi-gear manual transmission according to claim13, wherein the range group is a planetary gear set (2P).